Reference for Yevamot 153:3
מכל מקום קשיא הכא תרגמו (תהלים מה, יד) כל כבודה בת מלך פנימה במערבא אמרי ואיתימא ר' יצחק אמר קרא (בראשית יח, ט) ויאמרו אליו איה שרה אשתך וגו'
on a point of law, and such a point comes up [for a practical decision], he is obeyed if his statement was made<span class="x" onmousemove="('comment',' In the course of his discourses and studies. ');"><sup>9</sup></span> before the event;<span class="x" onmousemove="('comment',' Before the point of law assumed practical importance. ');"><sup>10</sup></span> but if it was not so made he is not obeyed! Here the case was different, since Samuel and his <i>Beth din</i> were still living.<span class="x" onmousemove="('comment',' Had not the statement been a true on, he would not have ventured to make it when its validity could be so easily tested. ');"><sup>11</sup></span> The difficulty,<span class="x" onmousemove="('comment',' Raised by Doeg (supra 76b) to which no reply was forthcoming ');"><sup>12</sup></span>